Hello Adam,
Have you tried connecting the 2416 to our itools? This might be the easiest option just to confirm that the basic comms is ok, itools will automatically scan 9600, 19k2 & will also scan for the Modbus address too.
Some RS485 converters you need to set the baud rate, have you done this?

Yes - I’ve tried iTools, but I have to admit, I didn’t read any manuals. I opened the server, then config, enabled the comm port and restricted the baud, I’m 1000% certain that the bad is set to 9600. I watched it scan thru my address and ok the scope and never see a response. I wasn’t sure how to set iTools for 2 or 4 wire mode, it seems like it would need to know, because in 2 wire mode, it gets a copy of everything it transmits in its receive buffer.

Are there any specific instructions for iTools I should be following? I didn’t get an install key, but that didn’t seem necessary to get it to do basic comms...

Again, I never see the REM light blink on the display when it receives characters. Can you confirm that this light should blink when characters are received? Or does it blink when validated Modbus messages are received?

Is there a global comms enable setting somewhere in the FW?

Anything else? I’ll try and post a scope shot of it when I get into the office. At this point I have 4 units, they are all behaving the same. I’ve gone as far as taking the backs off and confirming the 2 wire 485 modules are installed. All FW reports “Cm5” - so I think the modules exist and are being detected correctly.